Sandwich me Avgo is the plainest entry in the Greek sandwich-counter repertoire: an egg sandwich, built cold, sold from the same case as the ham-and-cheese and the tuna. It is national rather than regional, which is another way of saying it belongs to no one place and to every bakery, kiosk, and zacharoplasteio chiller in the country. The angle worth taking is exactly that ordinariness. This is the sandwich you reach for when you want something filling and unfussy, and the whole question is whether the kitchen treated a cheap filling with any care.
The build is short, so each step carries weight. The egg is hard-boiled, peeled, and either sliced into rounds or mashed with a little mayonnaise. Bread is whatever the counter runs, usually a soft white roll or a sliced sandwich loaf, sometimes lightly buttered on the cut faces. Salt and pepper go on the egg, not as an afterthought. Good execution means eggs boiled to a set but still tender yolk, no grey ring, seasoned while assembling so the salt actually reaches the filling. Sloppy execution shows up as overcooked rubbery whites, a chalky yolk, dry untoasted bread doing none of the work, and a mayo-bound mash that has gone slick and loose from sitting warm in the case. Because there is no strong flavor to hide behind, every shortcut is visible on the first bite.
It shifts in small, honest ways. Some counters keep it as sliced egg with a leaf of lettuce and a few rounds of tomato, closer to a salad in bread. Others go fully to egg-mayo mash, sometimes with a pinch of mustard or chopped dill folded through. The egg-and-bacon version, where bacon joins the egg in the same roll, is a related build that deserves its own article rather than being crowded in here. Left as itself, Sandwich me Avgo is a quiet test of a counter: get the egg and the seasoning right and a cheap sandwich becomes genuinely good; get them wrong and there is nowhere to hide.